Back-to-back seating unit



FIG. 1 is an isometric view of the back-to-back seating unit of my design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a front elevational view thereof, the back elevational view being identical thereto; and,

FIG. 4 is a left side elevational view thereof, the right side elevational view being identical thereto.

The broken line showing in the drawing figures is for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a back-to-back seating unit, as shown and described. 